Funding for this research was provided by:
Cyrus Tang Foundation (NA)
Received: 9 October 2018
Accepted: 21 May 2019
First Online: 7 June 2019
Ethics approval and consent to participate
: Written infomed consent was ontained from all study participants before conducting the campaign and the physical examinzation. The study protocol, consent forms, and survey questionnaires were approved by the Tsinghua University Human Participants Ethics Committee (ref: 20170024) on September 22, 2017.
: Not applicable
: The authors declare that they have no competing interests.